Apparatus for measuring transverse accelerations



Oct. 18, 1955 M. KEMPTON APPARATUS FOR MEASURING TRANSVERSE ACCELERATIONS INVENTOR L. KEMP TON Filed April 14, 1952 MARVIN By @Baflmm ATTORNEYS United States Patent APPARATUS FOR MEASURING TRANSVERSE ACCELERATIONS I Marvin L. Kempton, Socorro, N. Mex., assignor to the United States of America as represented by the Secretary of the Navy Application April 14, 1952, Serial No. 282,145

7 Claims. (Cl. 264-1) This invention relates to artillery weapons, and in particular to an arrangement for determining acceleration forces developed by a projectile in a gun barrel.

Upon acceleration of a projectile in a rifled gun barrel or tube, acceleration forces of large magnitude are developed by the projectile during the period that the projectile is traversing the gun tube. These forces are caused by the projectile striking the inner faces of the gun tube during rotation of the projectile.

It is of particular importance from a design standpoint to know the value and location of the acceleration forces generated so that certain fuze components, such as oscillator-detector tubes, amplifier tubes, and thyratron tubes of radio proximity fuzes, can be properly mounted in order to prevent them from being damaged during the critical period that the projectile is' traversing the gun tube. The gun designer, likewise, is interested in the acceleration forces in designing tubes to withstand such large forces.

It is the principal object, therefore, of this invention to provide an arrangement for measuring ttransverse acceleration forces developed in a gun tube during the period that a projectile is traversing the gun tube.

Another object of the invention is to provide an arrangement for continually recording transverse acceleration forces during the entire period that the projectile is in the gun tube.

To provide a simple system for recording acceleration forces that can be readily mounted into a projectile fuze, is still another object of this invention. 1

Other objects and many of the attendant advantages of this invention will be more fully appreciated as the same becomes understood by reference to the following detailed description when considered in connection with the accompanying drawing, and in which:

Fig. l is a longitudinal sectional view of a projectile fuze, embodying the invention;

Fig. 2 is a cross-section along line 2-2 of Fig. 1; and

Fig. 3 is a cross-section along line 33 of Fig. 1.

In accordance with the invention, an acceleration gage is mounted in a projectile fuze to record the developed acceleration or side slap forces. This gage includes a carrier ring, which, upon longitudinal acceleration of the projectile, due to the effect of inertia, is caused to remain substantially without rotation. This carrier ring contains certain balls which move spirally down a casing and score a multi-spiral trace on the surface of a magnesium rod, for indicating the magnitude of side acceleration forces in a rifled gun, such as a howitzer or field artillery gun. The magnesium rod is limited against full rotation by a plurality of pins, but is caused to rock on a hearing by the side or transverse acceleration forces. The free end of the rod moves in accordance with the side acceleration forces developed by the projectile. The magnitudes of the side acceleration forces developed by the projectile in the gun barrel are then determined by measuring the depths of the score marks on the magnesium rod and then converting this data into acceleration forces, using other known information.

Referring now to the drawing for a more detailed description of the invention, there is shown in Fig. 1 an inert artillery fuze 10 having a nose 12 and a body 14, which contains a gage arrangement 16 for recording the acceleration force data.

Nose 12 is internally threaded at 18 so that it can be screwed onto a portion 20 of the threaded section 22 of the fuze body 14. Set screws 24 are utilized for preventing the nose 12 from moving relative to the fuze body 14. Portion 26 of the threaded section 22 of the fuze body 14 is used for attaching the assembled fuze 10 to a projectile (not shown).

Fuze body 14 is internally bored, and has, therefore, three bore sections 28, 30 and 32. Bore section 28 is internally threaded throughout its length, as indicated at 34, and into it is screwed a threaded plug element 36 which is used to support a rod member 38, which will be described presently. Plug element 36 thus occupies a position usually occupied by the conventional detonatorbooster arrangement (not shown) for igniting the main explosive charge carried by the projectile proper.

The acceleration gage arrangement 16, with which this invention is particularly concerned, is located in bore section 30. Bore section 30 is of smaller diameter than bore section 28, and it has a threaded portion 39 and an unthreaded portion 40. Threaded portion 39 is, in reality, a spiral groove having a quadruple Acme thread with a 1" lead.

A cylindrical carrier ring 42, having an external threaded surface 44 corresponding to the threaded spiral groove portion 39, is located within the bore section 30. This carrier ring 42 is divided into two sections 45 and 46 in order that a plurality of balls 48, usually four in number and in diameter can be mounted therein. These balls 48 are mounted adjacent to magnesium rod 38 and are spaced equally thereabout. Balls 48 are silver soldered in their mountings as indicated at 52.

Magnesium rod 38 extends throughout the length of bore 30, and it has one free end 54 and a pivoted end 56.

Magnesium rod 38 is limited against full rotation by a plurality of pins 58 which are mounted in plug element 36. These pins 58 extend into slots 60 cut into end 56 of rod 38. A V-notch 62 formed in the center of plug element 36 receives a ball 64 upon which the pivoted end 56 of magnesium rod 38 is mounted. Ball 64 thus acts as a bearing for rod 38 so that the rod 38 can be caused to rock by the side acceleration forces since the other end 54 of the rod 38 is free to move. A washer 66 is located between the unthreaded portion 48 of bore 30, and plug element 36.

Rod 38, together with carrier ring 42 and balls 48 are assembled through end 68 of fuze body 14. A plug element 70 is located in bore section 32, and is maintained in position by the threaded arrangement 72.

In operation, upon acceleration of the projectile, the effect of inertia causes carrier ring 42 to remain substantially without rotation. Balls 48, together with the carrier ring 42, move spirally down bore section 35), and the balls 48 score a quadruple spiral trace on the surface 72 of magnesium rod 38, and thus indicate the magnitude of side acceleration forces in the rifled gun. The projectile can be recovered by vertical firing.

Rod 38 is limited against full rotation by pins 58, but is caused to rock, by the side or transverse acceleration forces, on bearing arrangement 64.

The upper end of rod 38 is, as previously pointed out, free to move in accordance with the side acceleration forces. The amount of side acceleration of the projectile can then be determined by measuring the depth of the 1. An arrangement for recording transverse accelera-i tion forces developed by a projectile during the period that said projectile is traversing a-gun tube, comprising, a substantially cylindrical and deformable record receiving blank having one end thereof pivotally mounted within said projectile, said record receiving blank being-: held axially of said projectile, and an inertia operated means surrounding said deformable blank for recording a permanent spiral record on said blank, whereby upon longitudinal acceleration of said projectile in said gun tube, said inertia operated means records said spiral record on said record receiving blank of the transverse acceleration forces developed during the time period that said projectile is traversing said gun tube.

2. An arrangement for recording transverse acceleration forces developed by a projectile during the period that said projectile is traversing a gun tube, comprising, a substantially cylindrical and deformable record receiv ing blank having one end thereof pivotally mounted within said projectile and the other end free, said record receiving blank being held axially of said projectile, and an inertia operated means surrounding said deformable blank for recording a permanent spiral record on said blank, whereby upon longitudinal acceleration of said projectile in said gun tube, said inertia operated means records said spiral record on said record receiving blank of the transverse acceleration forces developed during the time period that said projectile is traversing said gun tube.

3. An arrangement for recording transverse acceleration forces developed by a projectile during the period that said projectile is traversing a gun tube, comprising, a housing mounted within said projectile, a substantially cylindrical and deformable record receiving blank having one end thereof pivotally mounted within saidhousing and the other end free, said record receiving blank being held axially of said projectile, and an inertia operated means located between said housing and said deformable blank for recording a permanent spiral record on said blank, whereby upon longitudinal acceleration of said projectile in said gun tube, said inertia operated means records said spiral record on said record receiving blank of the transverse acceleration forces developed during the time period that said projectile is traversing said gun tube.

4. An arrangement for recording transverse acceleration forces developed by a projectile during the period that said projectile is traversing a gun tube, comprising, a housing mounted within said projectile, a substantially cylindrical and deformable record receiving blank having one end thereof pivotally mounted within said housing and the other end free, said record'receiving blank being mounted axially of said projectile, and an inertia operated means located between said housing and said deformable blank for recording a permanent spiral record on said blank, whereby upon longitudinal acceleration of said projectile in said gun tube, said inertia operated means records said spiral record on said record receiving blank of the transverse acceleration forces developed during the time period that said projectile is traversing said gun tube.

5. An arrangement for recording transverse acceleration forces developed by a projectile during the period that said projectile is traversing a gun tube, comprising, a housing mounted within said projectile and having its principal axis parallel to the longitudinal axis of said pro jectile, said housing having a spiral groove threaded into its internal surface, a substantially cylindrical and deformable record receiving blank pivotally mounted at one end thereof within said housing and the other end free,

said record receiving blank being mounted axially of said projectile, and an inertia operated means located between said housing and said deformable blank for recording a permanent spiral record on said blank, said inertia operated means having a threaded portion to cooperate with said spiral groove in said housing, whereby upon longitudinal acceleration of saidprojectilein said gun tube, said inertia operated means records said spiral record on said References Cited in the file of this patent UNITED STATES PATENTS 2,445,307 Mindlin July 13, 1948' 2,523,474 Mason Sept. 26, 1950 2,575,973 Perry Nov. 20, 1951 2,597,758

Sreb May 20, 1952, 

